Okay, it looks like the discussion I was looking forward to didn't take place in this thread but the correspondingly themed thread in the fan art section
(if you seriously want to call that a discussion because it never moved beyond the first part of my treatise
I'm probably the only one to blame for not having chosen the alternate thread heading (i.e. "How to see Yesterday's Enterprise from different angles"
One constructive criticism of the treatise had been how I could even propose that the events took place in an "alternate universe" while everybody is talking about an "alternate time line" (in "our" universe).
I found this comment from director David Carson, the director of "Yesterday's Enterprise" and its 'sequel' "Redemption, Part II" rather interesting:
“I particularly liked the challenge of “Yesterday’s Enterprise” because we were creating the Enterprise in a different and parallel time line: An Enterprise at war.”
(Starlog ST-TNG magazine Vol. 19, Spring 1992).
A "parallel time line" is not "our" time line, it's parallel to ours (which was my suggestion at the end of Part II
of the treatise), and as such it is practically indistinguishable from an alternate universe.
David Carson also said that he took part in the concept meetings. The two original concepts for "Yesterday's Enterprise" were entirely Novikov self-consistency principled, i.e. in one the Enterprise-C did show up in our universe and Picard needed to persuade the crew to go back and fulfill history, in the other one Sarek had to fulfill history by taking Surak's place.
Possible that David Carson understood the paradigm shift when Tasha Yar became a part of the story (apparently no longer self-consistency principled, i.e. the present somehow miraculously changed), hence his "parallel time line" remark instead of "alternate time line".
How did the screenwriter Ronald Moore feel about the issue in retrospect?
It had been recorded that the scriptwriters were unhappy about their screenplay for "Yesterday's Enterprise" because it had been rushed.
I'd say that "Redemption, Part II" would have been an opportunity to fix some of the existing plotholes from "Yesterday's Enterprise" but what did Ronald Moore do?
GUINAN: I know that. But I also know she was aboard that ship and she was not a child. And I think you [Picard] sent her there.
GUINAN: You can't just dismiss this. If I'm right, then you are responsible for this whole situation.
SELA: Yes, she was on that ship twenty four years ago. She was sent there by you from the future.
Unless I own a censored and shortened version of "Yesterday's Enterprise", I do not recall that Captain Picard ever ordered Tasha Yar to go back in time aboard this Enterprise-C
, on the contrary he opposed the whole idea of sending someone from the "present" back in time (with knowledge of the future
And if anybody was ever "responsible" for Tasha Yar getting this idea of travelling back in time and being "responsible for this whole situation", it would definitely not be Picard but Guinan herself (or Q).
On the other hand, if everything stated in "Redemption, Part II" is correct, than the Tasha Yar that arrived in "our" universe was ordered / sent by Captain Picard (of an alternate universe), but not the alternate reality of "Yesterday's Enterprise".